This invention involves improvements in a generally known type of copolymer that is formed by addition polymerization of alpha unsaturated monomers (including vinyl monomers, alpha-olefins, and acrylates) and esters of unsaturated dicarboxylic acids or anhydrides (typically maleic anhydride). When provided with hydroxyl functionality, this type of polymer has found utility in prior art coating compositions where they can be cured to form durable coatings by reaction with crosslinking agents that are reactive with hydroxyl groups, such as polyisocyanates, aminoplasts, or anhydrides. Alternatively, this type of polymer has been proposed for use as a polymeric dispersant or surfactant.
U.S. Pat. No. 3,270,088 (Hicks) discloses alkoxylating a half ester of maleic acid to produce a hydroxyalkyl ester monomer that is copolymerized with vinyl monomers that do not contain other reactive functional groups.
U.S. Pat. No. 3,414,635 (Edwards et al.) discloses reacting an unsaturated anhydride with a glycol ether, and the resulting half ester is then alkoxylated. The resulting hydroxyalkyl diester is copolymerized with vinyl monomers or acrylate monomers that do not contain other reactive functional groups.
U.S. Pat. No. 3,838,087 (Pirck) discloses copolymerizing maleic anhydride with a vinyl aromatic monomer, then opening the anhydride groups with alcohol and alkoxylating the remaining acid groups to form a hydroxyl group containing polymer.
U.S. Pat. No. 5,612,416 (McCollum et al.) discloses alkoxylating a half ester of maleic acid to produce a hydroxyl group containing monomer that is copolymerized with a combination of vinyl monomers and alpha-olefins, neither of which contain other reactive functional groups.
U.S. Pat. No. 5,585,427 (Schimmel et al.) discloses copolymerizing unsaturated diesters with various vinyl monomers, followed by transesterification of ester groups with hydroxy polyethers. The vinyl monomers do not include acid functionality. The product is useful as a dispersant for pigments in coating compositions.
U.S. Pat. No. 5,166,272 (Burks et al.) discloses copolymers of unsaturated anhydrides and alpha-olefins that have at least eight carbon atoms. The alpha-olefins used are selected from 1-decene, 1-dodecene, and undecenylic [sic] acid. The patent discloses base-neutralizing the anhydride groups on the polymer to permit dispersing the polymer in water.
Canadian Patent Specification 1,159,990 (Plum) discloses reacting unsaturated anhydrides with a polyhydric alcohol and a monoepoxy compound and then copolymerizing the resulting hydroxy diester with unsaturated monomers explicitly without carboxylic groups, particularly vinyl aromatic monomers and acrylate monomers.
U.S. Pat. No. 4,289,866 (Ritz et al.) is similar to the Canadian Patent above, with an additional step of further alkoxylating the alcohol ester group.
U.S. Pat. No. 5,418,306 (Shalati et al.) has as its objective the production of acid functional polymers. An unsaturated anhydride is copolymerized with a polyolefin, and the resulting anhydride polymer is reacted with alcohol to convert the anhydride groups to acid functional half esters.
U.S. Pat. No. 5,418,307 (Valpey et al.) is related to the above patent, with the additional step of hydrogenating the copolymer to produce a saturated product.
U.S. Pat. No. 4,166,893 (Kambanis et al.) copolymerizes a dimaleate having selected ester groups with a first acrylate and a second unsaturated monomer selected from other acrylates, vinyl acetate, and styrene.